APPENDICEAL INVOLVEMENT AS A SKIP LESION IN ULCERATIVE-COLITIS

Despite the frequency of ulcerative colitis (UC), and numerous studies related to this disease, controversy remains regarding its distributi on patterns. It is generally believed that UC starts in the rectum and progresses proximally in continuity to involve cecum along with appen dix in 50% of all cases. However, recent endoscopic and histological s tudies suggest that UC can occur as a discontinuous process. Furthermo re, the few existing studies specifically addressing appendiceal histo logy in UC are divided over whether ulcerative appendicitis (UA) may b e seen without cecal involvement (i.e., as a ''skip lesion''). To stud y the appendiceal pathology in UC, and in particular the frequency of UA as a ''skip lesion,'' we retrospectively evaluated 39 proctocolecto my specimens containing appendices removed for UC. Six cases (17%) had obliterated appendices; appendiceal and cecal histologies of the rema ining 33 cases were divided into (a) active disease, (b) quiescent dis ease, or (c) nonspecific or normal histology. Twenty of 39 appendices (51%) showed active disease, four (10%) had quiescent disease, and nin e (23%) were either normal or nonspecifically inflamed. After exclusio n of one case for inadequate cecal sampling, comparison of cecal and a ppendiceal histologies showed concordance in 16 cases and discordance in the remaining 16. Of these discordant cases, six had greater diseas e activity in the cecum and 10 had greater activity in the appendix. O f these latter 10 cases, six showed normal or nonspecific cecal histol ogy associated with active UA. Thus, ''skip lesions'' of the appendix were detected in 15% of the UC specimens examined.